<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- <meta name="viewport" content="width=device-width, initial-scale=1.0"> -->
    <title>媒体查询</title>
</head>
<body>
    <div class="main"></div>
</body>

<style>
/* 在大于750px的设备，把背景色显示为red
在大于375px的设备 小于750px，把背景色显示为green 
在媒体查询时候，建议从小到大书写
*/
@media screen and (min-width:350px){
    .main{
        background-color: green;
        height: 600px;
    }
}

@media screen and (min-width:750px) {
    .main{
        background-color: red;
        height: 600px;
    }
}


</style>
</html>